Effects of C-peptide on forearm blood flow and brachial artery dilatation in patients with type 1 diabetes mellitus

Acta Physiol Scand. 2001 Jul;172(3):159-65. doi: 10.1046/j.1365-201x.2001.00860.x.


Recent studies suggest that C-peptide increases blood flow in both exercising and resting forearm in patients with type 1 diabetes. Now we have studied the effect of C-peptide administration on endothelial-mediated and non-endothelial-mediated arterial responses as well as central haemodynamics in 10 patients with type 1 diabetes in a placebo-controlled double-blind study. Euglycaemia was maintained with an i.v. insulin infusion before and during the study. A high-resolution ultrasound technique and Doppler echocardiography were used to assess haemodynamic functions. Brachial artery blood flow and brachial artery diameter were measured in the basal state, 1 and 10 min after reactive hyperaemia and 4 min after sublingual glyceryl trinitrate administration (GTN; endothelial-independent vasodilatation), both before and after the end of 60-min C-peptide (6 pmol kg-1 min-1) or saline infusion periods. Echocardiographic measurements were also performed before and at the end of the infusion periods. Seven healthy age-matched males served as controls for vascular studies. The patients showed a blunted brachial dilatation after reactive hyperaemia in comparison with the healthy controls (2.1 +/- 0.5% vs. 9.3 +/- 0.3%, P < 0.001), indicating a disturbed endothelial function. C-peptide infusion compared with saline resulted in increased basal blood flow (33 +/- 6%, P < 0.001) and brachial arterial dilatation (4 +/- 1%, P < 0.05). Left ventricular ejection fraction seemed to be improved (5 +/- 2%, P < 0.05) at the end of C-peptide infusion compared with placebo. The vascular response to reactive hyperaemia and GTN was not affected by C-peptide infusion. Our results demonstrate that physiological concentrations of C-peptide increase resting forearm blood flow, brachial artery diameter and left ventricular systolic function in patients with type 1 diabetes.

Publication types

  • Clinical Trial
  • Clinical Trial, Phase I
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / metabolism
  • Blood Pressure / drug effects
  • Brachial Artery / drug effects*
  • C-Peptide / pharmacology*
  • Diabetes Mellitus, Type 1 / physiopathology*
  • Echocardiography, Doppler
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiology
  • Female
  • Forearm / blood supply*
  • Heart Rate / drug effects
  • Hemodynamics / drug effects
  • Humans
  • Insulin / blood
  • Male
  • Regional Blood Flow / drug effects
  • Vasodilation / drug effects*


  • Blood Glucose
  • C-Peptide
  • Insulin